Ask any successful entrepreneur about the key to his or her success, and confidence is likely to be near the top of the list. That’s because entrepreneurs must be independent while connecting with the right people, levelheaded while taking risks, and big-dreamers while being utterly realistic about their prospects—all of which are fueled by self-confidence.

Conventional wisdom says that confidence is something you’re born with or learn early. But the fact is that confidence can be achieved through effort and determination.

Here are four concrete ways to increase your confidence, and therefore your possibilities, productivity and success as an entrepreneur.

1. Rid your life of negativity.

If you want to live a positive, joyful life, you cannot surround yourself with negative people who don’t support or encourage your happiness. There will always be consistently negative people who constantly try to bring you down. Don’t allow these people to sap your confidence. This may be easier said than done, especially if you work with naysayers. Try to distance yourself from anyone who isn’t good for you or your business. Make it a daily practice to focus on cultivating new, positive relationships and let go of the negative ones.

2. Organize your business.

Creating a clear roadmap of where you are, where you want to go and how to get there will make you more confident by grounding you in reality and action. Write down your goals in the form of daily to-do lists, weekly task-based schedules, monthly progress reports that track your successes and an annual business plan that evolves alongside your professional development.

Knowing your history will make you more confident about the present and future by showing you where you’ve been and how far you’ve come, providing proof that you’ve advanced, and an inspirational vision of how far you could go.

3. Stay healthy.

Succeeding in business requires hard work, and that takes energy. Increase your energy by paying attention to the essentials: diet, exercise and rest. Eat nutritious foods, including balanced meals and nourishing snacks that make you feel refreshed and ready for your next challenge. Stick to an exercise routine that replenishes you, whether it’s individual activities (like walking, biking or working out at the gym) or group sports that build your confidence as part of a team that works together towards a common goal. And get a full night’s sleep as often as possible so you wake up every morning with a get-up-and-go attitude.

4. Practice power poses.

Here’s something you can do this very minute that will make you feel more confident right away, courtesy of social psychologist Amy Cuddy. Her research shows that we can feel better about ourselves simply by changing our stance.

In her now-famous TED Talk, Cuddy discusses how “power posing” (that is, striking a positive posture, for example like a superhero) actually changes our physiology by increasing the cortisol in our brains. Practice in private and you may notice an immediate improvement. Try this technique out in public (though maybe in more subtle forms) and see if people respond positively to your body language.

These exercise will serve you well if you actually use them on a regular basis. You’ll be more confident about yourself and your potential, which will benefit your business and life. Confidence is your most important asset, so don’t delay. Take action to start feeling more confident today.

Jacqueline Whitmore

Jacqueline Whitmore is an etiquette expert and founder of the Protocol School of Palm Beach in Palm Beach, Fla. She is the author of Poised for Success: Mastering the Four Qualities That Distinguish Outstanding Professionals (St....